How To Choose A Dental Chair Oral Lamp

Toothache hurts!

We rely on our dentists to stop it and even better to prevent it. And our dentists rely on their tools. They need to be able to see what they are doing, clearly and without undue fatigue. The sufferer is only too likely to say that “a bad workman blames his tools” but there are several important factors to consider when choosing the right oral lamp.

One of the significant advances for the dentist in recent years is the improvement in dental lighting. Designed to illuminate all corners of the mouth, accurately relay colors, and help reduce muscle fatigue for the dentist and his team, there is a wide variety to choose from.

The oral lamp does not work alone in providing excellent lighting. It works in conjunction with the overhead or background lighting. You need proper illumination to give your patient the best and highest quality dental care at the same time making life as easy and pleasant as possible for yourself. After all, you are likely to be spending many hours peering into oral cavities!

We discuss the types of lighting, the requirements for dentist and patient and look at the things you might need to consider when choosing your dental oral lamp. Whatever lighting you decide on, both the main light and the focussed narrow brighter light need to work in harmony to achieve the best results.

How much light is right for you?

How much light do you need – and where should it be focussed?

We measure light in lux. (lx) The lux is defined in the International System of Units (SI) as the amount of light where “one lux is the amount of illumination provided when one lumen is evenly distributed over an area of one square meter”. It is a way of defining the intensity of light. The lumen refers to the total light emitted. (The Oxford English dictionary defines a lumen as “The SI unit of luminous flux, equal to the amount of light emitted per second in a unit solid angle of one steradian from a uniform source of one candel nd it comes from the Latin word for light.) 

You must have a strong light to see inside the mouth, avoiding shadows and allowing excellent color discrimination. You will need a stronger focussed light that than supplied to a typical office –that is around 1,000 lux or less. But you don’t want to blind your patient with the glare of a powerful light from which they cannot escape!

Dental lighting needs both a wider background illumination and a narrow, brighter beam for focussing on the task in hand. The narrower beam can produce dark shadows and glare, and the main light reduces these but might need frequent positional readjusting, especially on those areas that are hard to access. Some overhead dental lights will shine the light in different directions at the same time – thus overcoming shadowy problems.

A headlight with a narrower beam but a brighter illumination will move with the dentist’s head and it is easy to focus on the desired spot, and a handpiece lamp moves with the hand as the hand moves over the teeth, spotlighting the area of concern.

Looking at the basics

There are three main  factors to take into consideration:

  • Bright enough light – reduces eye fatigue
  • Excellent color discrimination – accurate diagnosis depends on this
  • Ergonomic positioning – sometimes overlooked but it is important to protect the dentist from muscle fatigue

What should you consider when buying a dental light?

You need uniform lighting without dark corners and shadows. This is where the background light and the oral lamp work in synergy.

When you eliminate the shadows the strain in your eyes is reduced.

Look for the light pattern. When the light has a softer edge and not a sharp cut-off, you will find the strain on your eyes is less when you look away. The light still needs to show the inside of the mouth clearly – but the edges can be feathered.

It’s best if the light does not shine into the eyes of your patient!

What is the intensity of the light?

The intensity for an oral light ranges from 15,000 lux to 30,000 lux).

The background illumination to dental lamp ratio

To reduce eye fatigue you need a suitable ratio between the background and the target lights (TB). In other words the (TB)ratio between the mouth and face and the area you are working on. A suggested TB ratio of 3:1 – 5:1 will help to reduce eye strain and help you see more clearly. In other words, the target area should be lit about three times more brightly than the background.

The ambient light v the task light

To minimize the glare and any shadows a recommended ratio between the background light and the focussed task lighting should be around 1:3 or 1:5. So, if the task lighting is 20,000 lux then the background light should be around 4,000 lux. This gradient helps to reduce eye strain while maintaining a comfortable light level for your patient.

Color discrimination

Accurate color discrimination is essential for correct diagnosis. It helps you differentiate the surfaces easily and enable you to make the procedures you carry out finer and more delicate.

Sunlight has perfect color rendering – ie a Color Rendering Index (CRI) of 100. The best artificial light to copy sunlight is white light, so look for a light with a high CRI.  A CRI of 94 will give you the good color discrimination every dentist needs. But light from the window is not essential since your specialist dental light quality is similar to daylight.

Colors are also measured by a scale that reflects how warm or cool they appear. Warm colors like yellow are around 2,700 – 3,000 Kelvin and cooler colors like blue may be over 5,000 Kelvin. Daylight is 5,000 Kelvin but if the sky is clear this can rise to 27,000 Kelvin. While you need colors in the higher Kelvin range to work with, your patients in your waiting room will probably prefer lower temperatures. You will probably find a range of between 3,500 Kelvin and 6,500 Kelvin works well for you, using a white light source.

Ergonomic positioning. Can you position the lamp for greater clarity?

You will be working for hours and back strain can be a major problem for the dentist if the oral lamp is not poisoned correctly and won’t light up the target places as you move. This affects other members of your team as well. You and your assistants are likely to glance up from the mouth two or more times every minute, so it is important to make sure that your ergometric positioning is correct to avoid repetitive injury.

You will need to check – how easy is it to position the headlight? Can you shine the light exactly where you need it?

Check out a number of positions you might need when you are working. You might find that a third axis of rotation lest you see inside your patient’s mouth even when you need to reposition their head. A headlight alone can cause shadows especially when working on the mandible, and fingers and instruments get in the way. The dentist twists his head to try to see and even though the movement can be slight, over the course of the day it can readily build up to poor posture, fatigue, and eye strain. When you use both a headlight and a top light in harmony this helps to solve this problem.

Suggested step to ensure the lighting is right for you

  1. Switch off the headlamp and overhead light.
  2. Turn on the headlamp
  3. Adjust the headlamp slowly. Once it is bright, gradually lower the intensity till it is highlighting the area you want to work on.
  4. Turn on the overhead light.
  5. Position the headlight directly above the mouth – about 27 inches(68 cms) away from it.
  6. Note that the headlamp should be the brighter of the two light sources.
  7. You may need a third lamp to completely eliminate shadows.

Once this is set up, the movements of your head needed to maintain good illumination in all the areas you intend to work on will be reduced and muscle strain and fatigue will likewise be lessened.

Patient experience to reduce anxiety

We are all influenced by light, and your patients are likely to be nervous and apprehensive. A visit to the dentist is scary for many of us. But the lighting can make the experience feel more comfortable. When your patient is relaxed it makes it easier for you to do the work required.

Natural light is reassuring – you might be able to position the chair to face the window? This gives your patient something to look at as well! Soft lighting and calming colors as a background give a  pleasant ambiance to your surgery. The waiting area can be softly lit and calming.

You could choose lighting levels around 200-700 lux with downlighting and lights in recessed areas can add a modern scenario to your waiting area.

A brief summary of the figures

Your eyes take around six minutes to fully adapt to a change in light. You won’t have that amount of time in practice!

  • The range of daylight intensity lies between 2,000 to 100,000 Lux – a dentist needs around 20,000 lux.
  • The range of daylight color temperature lies between 2,000 to 27,000 Kelvin.
  • Dentists usually work in the range between 3,500 Kelvin and 6,500 Kelvin, the best lighting for examining the teeth is 4,500 Kelvin in daylight.
  • Color rendering should be at least 90%.
  • As you age your eyes need more light to perform in the same way.
  • To prevent eye strain you need optimum lighting conditions.
  • The higher the contrast between the headlamp and the overhead light the sooner your eyes will feel fatigued. A color ratio of 1:3 – 1:5 is recommended.
  • And it’s not just the dentist who ages – your fluorescent tube lights need replacing annually to maintain optimum efficiency.

Conclusion

When you choose your oral lamp you need to take two things into consideration: the quality of the lighting and how to minimize fatigue for yourself.

The oral lamp and the overhead light work together to reduce shadows from your fingers or instruments or the shape of the oral cavity.  But it does let you see around corners, that an overhead light alone cannot do. Sharp edges cause extra strain to your eyes.

Good color discrimination is necessary for accurate diagnosis, not only for tooth problems but also for the early diagnosis of oral cancers.

For the dentist, he or she is at risk of eye strain, headaches, back, and neck ache as well as the demands of the patients who are often apprehensive and might be in pain as well. So there can be considerable stress upon the dentist  – and getting the light exactly right plays a large part in making the working conditions more pleasant and free from stress. If you can’t see properly, if the light is dim and colors blurred, even a simple procedure can lead to errors and mistakes.

Dentistry is a skilled profession and both the dentist and the patient deserve the most effective lighting to minimize stress and to obtain the best view inside the patient’s mouth.